Means for fastening the blades in gas turbines and steam turbines



Dec. 25 1923.

- A. MEYER MEANS FOR FASTENING THE BLADES IN GAS TURBiNES AND STEAMTURBINES Filed Dec- 20. 1922 v Fig.4.

Fig.5-

Fig. 3.

Patented Dec. 25, 1923. p

1 UNI ED STA TES, NT 1 FF E.

'ADOLIEMEYER, OF ZURICH, SN'ITZEB-LAND, ASSIGNOR TO AKTIENGESELLSCHAFT IBROWN BQVERI & 01E, F BADEN, SWITZERLAND. I

MEANS non FASTENING THE BLADES In GAS TURBINES AND sTfEAM TUnBINns.

Application filed December 2c, 1922. Serial so; cosaoa' iug the Bladesin Gas Turbines and Steam Turbines, of which the following is a specification.

A known method of fastening the blades in gas turbines and steamturbines has been to suspend them from the spacing members, the spacingmembers themselves being ixed in the wheel discs or drums, In such casesthe fixing of the spacing members has been effected hitherto mostly bymeans of round, rectangular. or saw-tooth shaped projections engaging incorresponding grooves in the drum or disc.

Since, in view of the high strains, the

shank of the blade must not be weakened, the

designer has been compelledtoallow these projections or teeth of theblades to project beyond the edge of the blade, thus entailing at thesame time an extra thickening of the head of the, disc.

This accumulation of material at the outer periphery is an undue load onthe wheel disc, and has given rise to high stresses in the disc, or ithas compelled the thickening of the edge of the disc, with the result ofincreasing the consumption of expensive material and the cost ofmanufacture.

It is also known to make the blades of the last rows of turbines, whichare the blades most strained, in one piece with the spacing member, andto cause the blade-foot, strengthened in this manner, to clasp the edgeof the disc for thepurpose of being fastened thereto and thus producinga lighter rim for the disc. This necessitates however, the milling ofthe blades out of the solid cross-section of the foot, andcon-'sequently a very considerable increase in the cost of manufacture. I

The present invention has for its object to allow of the use of lightrims for the wheel discs, and to diminish the strains on d the discs,even when employing the indirect way of fastening the blades by means ofthe spacing members.

This is effected by causing the spacing members which carry the blades,to clasp the edge of a wheel disc in the manner illustrated by way ofexample in the figures of the accompany ng drawlngs 1n which Figure 1 isa radial cross-section of a turbine wheel disc comprising one ment ofthis invention. Y Y

Figures 2 and 3 are similar v1ews of two embodi- 3, further embodiments.

Figure 4: is a section, and Figure 5 isa section partly in front tion,and r I Figure 6 is alplan of a number of blades fastened to the wheelarse.

elevav In this construction the spacing members and the blades may beequalin width, that is to say, the rim of the wheel disc may be madenarrower thanthe blades as shown in Figure 1, or the spacing members maybe made wider than the blades, in which case the width of the rim of thewheel disc is i made equal to or approximately equal to the width of theblades as shown in Figure 2.

In orderto protect the claspingparts a of each spacing member frombending strains, the spa ing members may be provided with projections Z;which engage in corresponding grooves turned in the disc as shown inFigures 2 and 3; this expedient being already known per se in the caseof blades madein one piece with the spacing member.

The blades of the improved blade-fastening are provided, preferably byupsetting,

disc can be arranged with their outer sur-- faces so close together asto form a smooth surface obviating all windage.

The invention produces a blade-fastening of great simplicity andcheapness even for blades subjected to high strains, because the bladesas well as the spacing members can be made from drawn bars. The spacingmembers merely require to be cut to the length and formed with a recesscorresponding to the cross-section ofthe rim of the disc, whereas theblades are provided by, upsetting, with their feet or proj cations withwhich they are fitted between the spacing members.

By suitably cutting ofi' the spacing members on, thesteam side (edge 4!)the crosssectional passage area can be adapted very simply to the steamconditions.

What I claim is V I I 1.- In ameans for fastening turbine blades to awheel disc in a steam or gas turbine of the type wherein the turbineblades are.

carried by the blade-spacing members, the combination withthe wheel dischaving an under-cut rim and a turbine blade, of a blade-spacing membercarrying said blade clasping the. undercut rim of the. wheel disc.

2. In a means for fastening turbine blades to a wheel disc in a steam orgas turbine, of the type wherein the turbine blades are carried by thebladespacing members, the combination with the wheel disc having anunder-cut rim, and a turbine blade, of a blade-spacing member carryingsaid blade,

clasping the under-cut rim of the wheel disc, and a T-shaped foot onsaid turbine blade,

bearing upon the under-cut rim of the wheel disc. r

.3. In a meansfor fastening turbine blades to a wheel disc in-a steam orgas turbine of the type wherein the turbine blades are carried by theblade-spacing members, the combination withthe wheel disc, having anunder-cut' rim and a turbine blade, of a blade spacing member carryingsaid blade, wider ing the under-cut rim of the wheel disc, an

annular groove in the side of the wheel disc,

and a projection located on said blade-spacing 7 member, engaging insaid annular groove, whereby the clasping parts of said blade-spacingmember are relieved from bending strains. I V

ln-testimony whereof I have signed my name to. this specification.

' ADOLF MEYER.

